Deep Vein Thrombosis (DVT): Symptoms and Causes

What Is Deep Vein Thrombosis?

Deep vein thrombosis (DVT or venous thrombosis) occurs when a blood clot forms in a vein deep inside your body. DVT mainly affects the large veins in the lower leg and thigh, but can occur in other deep veins, such as in the arms and pelvis.

DVT can occur suddenly (acute), leading to an urgent or emergency situation. Or it can be a chronic condition, with blood clots gradually causing circulation problems, usually in the lower body. Chronic blood clots can lead to venous insufficiency, when your body has difficulty returning blood to your heart.

Thrombosis is a clot in a blood vessel. An embolism or thromboembolism is a clot that moves through your bloodstream. An embolism can become stuck in a blood vessel, blocking blood flow to your lungs, brain or heart. The embolism can cause severe damage, including pulmonary embolism, stroke or heart attack.

Causes of Deep Vein Thrombosis

Venous thrombosis is most common in adults over age 60, but it can happen to people of any age. Blood clots may form when blood flow in your veins slows down or becomes blocked.

DVT becomes more likely if you have one or more of these risk factors:

Being sedentary due to bed rest or sitting too long without moving, such as during travel
Family history of blood clots
Having a long-term (indwelling) catheter, a tube in a blood vessel
Obesity
Polycythemia vera, a condition that causes bone marrow to make too many blood cells
Pregnancy or childbirth in the past six months
Recent surgery or fractures in the hips, pelvis or legs

DVT Symptoms and Warning Signs

DVT most often affects large veins in the thigh and lower leg, usually on one side of the body. If the clot blocks blood flow, it can cause:

Red or darker-colored skin
Painful or swollen leg (edema)
Skin that feels warm to the touch

Diagnosing Deep Vein Thrombosis

Your doctor does a physical exam to understand what might be causing DVT symptoms. Our doctors often use vascular testing and diagnosis to rule out or confirm venous thrombosis. Your testing may include:

Complete blood count (CBC): This test tells your doctor how many of each type of blood cell you have in your blood. It can identify signs of infections or problems that could relate to clotting.
D-dimer blood test: This blood test looks for a protein that your body makes when it tries to break down a clot. A negative result rules out the presence of a thrombus (clot).
Doppler ultrasound exam: This test uses sound waves to provide images of blood flow in the area where there is a blood clot.
Pelvic MRI: If the blood clot is in the pelvis, such as after pregnancy, your doctor may order a pelvic MRI. This noninvasive test provides clear images of bones, soft tissue and blood flow in the area.

Your doctor may also order other blood tests to see if you have an increased chance of blood clotting. These tests may include:

Antithrombin III levels to show if you have enough antithrombin, which prevents excess clotting
Lupus-related problems, such as antiphospholipid antibodies or lupus anticoagulant, that mistakenly attack parts of your body’s cells
Genetic testing to look for mutations that make you more likely to develop blood clots, such as the prothrombin G20210A mutation or Factor V Leiden mutation
Levels of protein C and protein S, which help your body regulate clotting

Deep Vein Thrombosis Treatment at Penn

The first line of treatment for DVT is thrombolytic therapy. This treatment uses anticoagulant (anti-clotting) medication to thin your blood. The medicine can keep clots from growing and help prevent new clots from forming. Most people take blood-thinning medicine for at least three months after experiencing deep vein thrombosis (DVT).

Penn doctors may recommend:

IV heparin: Heparin is a powerful blood thinner that starts to work right away If you are hospitalized, your doctors may provide heparin through a vein (intravenously, through an IV).
Injectable heparin: This type of heparin, called low molecular weight heparin, is an injection given once or twice a day. You may not need to stay in the hospital if your doctor prescribes this type of heparin.
Warfarin: You take a warfarin (Coumadin or Jantoven) pill, often along with heparin. Warfarin takes several days to begin working.
Direct oral anticoagulants (DOACs): These medicines begin to work right away. Your doctor may prescribe them instead of heparin. Examples of DOAC medications include apixaban (Eliquis), dabigatran (Pradaxa), edoxaban (Savaysa) and rivaroxaban (Xarelto).
Xa inhibitors: These newer medicines work as well as warfarin and can be easier to manage. But it can be difficult to stop excess bleeding, so they are not right for everyone.

DVT Surgery Options

In rare cases, you may need surgery instead of or in addition to anticoagulants. Penn’s team of vascular surgeons provides advanced surgery to treat deep vein thrombosis and embolisms anywhere in the body. We also offer many endovascular procedures, which enable us to treat a blood clot by working through a blood vessel, without a large incision.

Your doctor may offer surgical or minimally invasive procedures including:

Endovascular procedures: Using small tools, surgeons, interventional cardiologists or interventional radiologists can remove a large blood clot (thrombectomy). We can also use these techniques to clear a vein or inject clot-busting medicines. Learn more about thrombolytic therapy and thrombolysis.
Stenting: Penn surgeons, interventional cardiologists and interventional radiologists can insert stents, tiny metal tubes that can hold open the vein. Our expertise enables us to insert stents into veins in your leg or pelvis (iliac veins) to manage DVT in different locations in your body.
Vena cava filter placement: Physicians place a filter in the body’s largest vein (vena cava). This filter captures blood clots and prevents them from traveling to the lungs.